Depends on where you are, the law is different from place to place.
Regardless of age, everyone is legally required to wear a helmet while biking. Depending on the country that you live in. UK for instanstance has no legal requirement to wear any sort of safety equipment on a bicycle.
Everyone has to wear a helmet no matter what age! :)
Legally it depends on if its a motorcycle or a bicycle and where you are, helmet laws aren't the same all over. In practical terms, the day to stop using a helmet is the day when you no longer think your head is worth protecting. Bottom line: you should always wear a helmet regardless of your age.
You should always wear a helmet to protect your brain from injury.
It is not illegal to ride a two or three wheeled motor vehicle without a helmet but some form of eye protection is required. On a Bike it is illegal to ride a bicycle without a helmet if you are under 16.
You can wear a helmet at pretty much any age. Depending on location and local laws, sometimes you don't have to wear a helmet once past a certain age.
A bicycle shop will have an appropriately sized helmet and someone on hand to help make sure the fit is correct.
The law isn't the same all over, so it depends on where you're at and how old you are.
It was a really old football helmet
It as implemented in 1999 that any person under the age of 16 must where a helmet hile bicycling in the state of Maine.
I think a helmet is a great idea, regardless of how old you are. Today they are comfortable enough to wear, and can protect you from nasty injuries.